MEGA-PRESS data quality

Data Processing
1

Hi all,

I’m trying to process our MEGAPRESS data (ACC voxel) using fsl-mrs, but I’m running into a couple issues.

First and most importantly, I’m not sure if there is enough signal in our data. When I plot the On, Off, and Difference spectra they mostly look like noise (attached below), but maybe this is the wrong thing to be looking at. Our protocol has a small voxel (10 x 20 x 10mm), which I know is much smaller than recommended, but just trying to see if there is anything salvageable from this set with respect to GABA measurement. Hopefully these plots can indicate what the issue is, if it’s not just too small of a voxel.

megapress_on_off_diff_grid
megapress_on_off_diff_grid1800×1050 216 KB

Second, assuming we have usable data, how can I add the MM3co component to a basis set? Are there fsl-mrs tools to easily create a gaussian (or multi-gaussian if that’s recommended) basis specific to the 3ppm component that I can add to the basis set?

Thanks so much for any help!

2

Hi,

the data looks unusable. 10x20x10 is very small for GABA. However, something else is wrong here.
Out of curiosity, could you share one of the datasets?

3

Thanks very much for the feedback – I’ll check on whether I’m allowed to, but based on the plots was there one in particular that would be more informative for troubleshooting?